Undercity by Andrew Wonder. It’s half an hour long, but the first 8:15 sequence in the subways is just incredible, and will probably hook you in for the rest. I put this up here because everything should have gone wrong. You have mixed light sources, low light, noise, moving subjects, handheld camera, very probable death, dismemberment, or arrest, and this guy mostly stays in focus. The film is an example of what one can do with these fancy small cameras. Wise editing keeps the pace intense. It’s easy to really root for the protagonist. Read more in an interview with the filmmaker here.